public void RegisterReceiver(BeatReceiver receiver, float maxDecay = 0.0f)
 {
     this.receivers.Add(new BeatDecay(receiver, maxDecay));
 }
 public BeatDecay(BeatReceiver receiver, float maxDecay)
 {
     this.receiver = receiver;
     this.maxDecay = maxDecay;
     this.curDecay = 0.0f;
 }